Henry of Kalkar (1328 – 20 December 1408) was a Carthusian writer.
Henry was born at Kalkar in the Duchy of Cleves. He began his studies at Cologne, and completed them at Paris, where he became Master of Arts in 1357. He forthwith occupied the post of procurator of the German nation in 1358, being also a professor of theology.
Having obtained canonries in the collegiate churches of St. Swibert in Kaiserswerth and St. George in Cologne in 1362, he returned to his native land. Soon after, however, disgusted with the world, he retired in 1365 to the Charterhouse of Cologne, where, owing to his talents and virtues, he was rapidly raised to the most important offices.
Successively prior of the Charterhouses of Arnheim (1368–72), of Ruremonde (1372–77), which he had built, of Cologne (1377–84) and of Strasburg (1384–96), which he restored, and visitor of his province for the space of twenty years, he was thus called upon to play, under the circumstances produced by the Great Schism, a considerable role in the Netherlands and German-speaking countries.
Relieved at length, at his earnest request, of all his offices, he retired in 1396 to the Charterhouse of Cologne, and there lived in recollection and prayer until his death.
Henry of Kalkar was celebrated not only as a writer, but also as a reformer. During his priorate at Arnheim he had the happiness and honour of "converting" one of his friends and fellow-students at Paris, Gerard Groote (the future founder of the Brothers of the Common Life), whom he attracted into his Charterhouse and directed for three years. "Moreover by his spiritual writings ... he exercised on the whole school of Deventer and Windesheim the influence of a recognized master." He was to this extent the organizer of the great movement of the Catholic Renaissance, which, initiated at Windesheim and in the convents of the Low Countries, went on developing throughout the fifteenth century, finding its definite expression in the Council of Trent.